STEMMUS-UEB v1.0.0: integrated modeling of snowpack and soil water and energy transfer with three complexity levels of soil physical processes

Abstract

Abstract. A snowpack has a profound effect on the hydrology and surface energy conditions of an area through its effects on surface albedo and roughness and its insulating properties. The modeling of a snowpack, soil water dynamics, and the coupling of the snowpack and underlying soil layer has been widely reported. However, the coupled liquid–vapor–air flow mechanisms considering the snowpack effect have not been investigated in detail. In this study, we incorporated the snowpack effect (Utah energy balance snowpack model, UEB) into a common modeling framework (Simultaneous Transfer of Energy, Mass, and Momentum in Unsaturated Soils with Freeze-Thaw, STEMMUS-FT), i.e., STEMMUS-UEB. It considers soil water and energy transfer physics with three complexity levels (basic coupled, advanced coupled water and heat transfer, and finally explicit consideration of airflow, termed BCD, ACD, and ACD-air, respectively). We then utilized in situ observations and numerical experiments to investigate the effect of snowpack on soil moisture and heat transfer with the abovementioned model complexities. Results indicated that the proposed model with snowpack can reproduce the abrupt increase of surface albedo after precipitation events while this was not the case for the model without snowpack. The BCD model tended to overestimate the land surface latent heat flux (LE). Such overestimations were largely reduced by ACD and ACD-air models. Compared with the simulations considering snowpack, there is less LE from no-snow simulations due to the neglect of snow sublimation. The enhancement of LE was found after winter precipitation events, which is sourced from the surface ice sublimation, snow sublimation, and increased surface soil moisture. The relative role of the mentioned three sources depends on the timing and magnitude of precipitation and the pre-precipitation soil hydrothermal regimes. The simple BCD model cannot provide a realistic partition of mass transfer flux. The ACD model, with its physical consideration of vapor flow, thermal effect on water flow, and snowpack, can identify the relative contributions of different components (e.g., thermal or isothermal liquid and vapor flow) to the total mass transfer fluxes. With the ACD-air model, the relative contribution of each component (mainly the isothermal liquid and vapor flows) to the mass transfer was significantly altered during the soil thawing period. It was found that the snowpack affects not only the soil surface moisture conditions (surface ice and soil water content in the liquid phase) and energy-related states (albedo, LE) but also the transfer patterns of subsurface soil liquid and vapor flow.

STEMMUS-MODFLOW v1.0.0: Integrated Understanding of Soil Water and Groundwater Flow Processes: Case Study of the Maqu Catchment, north-eastern Tibetan Plateau

“…Current SW-GW modelling work seldom considers the thermal effect and lacks real-case applications and verifications (see Appendix Table A2). The developed SW-GW coupling model in this work will facilitate 445 further the manipulation of sub-models with different complexity of vadose zone physics (thermal flow, soil water and heat coupling transfer, freeze-thaw, airflow processes; Yu et al, 2020b), surface hydrology (snowfall, Yu et al, 2021, runoff, Mastrotheodoros et al, 2020, connection with other relevant processes (soil and plant biogeochemical process, Yu et al, 2020a), towards an integrated groundwater-soil-plantatmosphere earth system modelling framework. 450…”

Disentangling the Impact of Event‐ and Annual‐Scale Precipitation Extremes on Critical‐Zone Hydrology in Semiarid Loess Vegetated by Apple Trees

“…(2011a, 2011b) developed the simultaneous transfer of energy, mass, and momentum in unsaturated soil (STEMMUS) model, which considers dry air as a single phase, and includes soil air pressure as a state variable in soil water and heat transport. This model has recently been successfully used to simulate hydrological processes in frozen soils (Yu, Fatichi, et al., 2020; Yu, Zeng, & Su, 2020; Yu et al., 2018, 2021). It has also been demonstrated that the incorporation of airflow improves the simulation accuracy of soil moisture when significant precipitation occurs (J. X. Wang et al., 2021; Yu, Fatichi, et al., 2020; Yu, Zeng, & Su, 2020, Yu et al., 2021).…”

Analysis on “three-box” model of stress-strain in frozen soil porous media based on representative macroscopic Volume

“…The frozen soil region is rich in natural resources, while many projects in China, such as energy, transportation, communication, water, and oil pipelines, are established in the frozen soil region (Zhang et al, 2015;Che et al, 2019;Ma et al, 2019;Streletskiy et al, 2019). The distribution and form of pore accesses in frozen soil vary, the momentum, energy, and mass transfer processes interact, and couple with each other, and the transfer phenomena and mechanisms are complex and variable (Sweidan et al, 2022;Yu et al, 2021;Fu et al, 2022). Some of the essential characteristics are difficult to obtain precisely (Alzoubi et al, 2019;Chang et al, 2019).…”